Coatings of the polyurethane type



a. r atuaaa Q Patented Nov. 28 1961 used. Because of the great reactivity of such compounds, we prefer to use the product of a partial condensation of m 3,010,949 the diisocyanate with, for example, a polyol, glycol, or tn' COAIINGS OF THE POLYURETHANE TYPE (hydroxy methyl) propane in a ratio of l mol of diisocya- Francis R. Charlton Pittsburgh Floyd D. Trischler A g I 1 l Bridgeville, and Steve N. Buco: Blairsville, Pa., assig 5 mate to each hydroxyl group of the polyol' The resulting condensation product is much less sensitive to atmospheric g iigg m Company a corporation of moisture. Such compounds react with the cross-linking N D i Fil d J 13 1953, S 703,379 agent more slowly to give a pot life of practical duration 3 Claims, (Cl. 260-47) (pot life being the length of time after mixing during which the composition can be applied to a surface). Ad vantageously, the compound Mondur CB may be used.

This invention relates generally to coatings for metal, This compound has the general formula:

Wood, glass, masonry, and concrete and more particu- 0 larly relates to coatings of the polyurethane type. g

While polyurethane coatings formed by the cross- 15 linking of di or polyisocyanates with compounds contain- 1 100 ing two or more active hydrogens are Well known, the 0 use to which such coatings can be put have heretofore ll been limited. The coatings have generally had either CH3 CH CCHZ OTCTNEC CH3 good resistance to chemical attack and poor resistance to p 0 0 physical attack such as impact, abrasion, and flexibility or had poor resistance to chemical attack and good resistance to physical attack. CHOfi-NH-CH3 it has now been found that urethane coatings with un- 0 expected and excellent properties with respect to both 00 chemical and physical attacks can be formed by the cross- The Polyhydroxyl polyalkaryl Polyether Prepared by linking of polyisocyanates with polyhydroxyl polyalkaryl the reaction of a phenol with P diepmfide of a P polyethers. The performance of the coatings of the hYdFOXYI polyalkaryl polyether m who of various heretofore known urethanes as compared with eqmvalems of phenc'l to each equlvalent 0f epoxlde the coatings of this invention are illustrated in the table vantageously be the type Sold under the trade name Epom below: These Epons have the following formula:

(1331a (|)H EH3 /O\ CHz C CHz --fi -O-CH2-OH-CHz l-Oqs-CO-OH2CH OHz CH3 |N CH3 Where N may be from (L25. Polyesters+ gg g ggii gy figfilgg? The phenol compound may be of the alkylated phenol Polyisocy- Polyisocy- Polyether+ 40 type such as ortho or para cresol and nonyl phenol. The mates mates 3333? phenol may be advantageously a halogenated phenol such as dichloro phenol or parachloro ortho cresol to Flex Excellent provide the coating with fire-resistance characteristics. p resistance a a o d 30. The compound may be formed in a conventional man- H 2: net as by the reactions discussed by Shechter and g ry a d. Wynstra in Industrial and Engineering Chemistry, vol- Aghesion $3- nine 48, No. 1, January 1956, 'pages 89-91, by heating the diepoxy polyhydroxy polyalkaryl polyether with The urethanes of this invention contemplate the prodphenol. net of the cross-linking of a polyisocyanate and a poly- The reaction mass described above has the general hydroxyl polyalkaryl polycther. The quantity of isoformula:

(1 ?Ha (RH (3H3 CH2C?CH2 0(l3 O-CH;CHCH1 -o-O 2-o-om-onpm OH CH; n CH3 '0 cyanates used in the preparation of the product is near Advantageously, to this hot reaction mass is added a the equivalent necessary for cross-linking with the hysuitable solvent such as methyl isobutyl ketone, Cellodroxyl grouping of the polyhydroxyl polyalkaryl polysolve acetate, ethyl acetate, and cyclohexanone to lower ether and advantageously may be in the range of from the viscosity. If the solvent is not added at this time, 0.75 to 1.5 equivalents of isocyanate groups for each the reaction mass sets to a glossy, solid mass and is difequivalent of hydroxyl group in the cross-linking agent. ficult to remove from the reaction vessel or to handle. Any of the organic polyisocyanate compounds commer- If desired, various pigments and fillers well known in the cially available such as toluene 2,4-diisocyanate, hexamethart may be added at'this time to give it color or body.

ylene diisocyanate, naphthalene 1,5-diisocyanate may be Such pigments and fillers include titanium dioxide,

The diepoxy polyhydroxyl polyalkaryl polyether may ad- 3 lithopone, iron oxide, carbon black,v china clay, and barytes.

A polyepoxide such as the epoxidized novalak resins described in copending application, Serial No. 708,439 may be substituted for the diepoxides of the Epon type. 5

' The reaction mass then has the general formula:

The invention is illustrated but not limited by the following examples in which parts and percentages are by weight.

4 and to high temperatures. Whereas the cured films of epoxy resins are known to have poor resistance to water and aqueous environments especially at elevated temperatures compositions of the present invention show excellent resistance to such environment.

What is claimed is: 1. A polyurethane coating comprising the reaction product of (a) an organic polyisocyanate I TCO with (b) a polyol having the general formula Example I To a flask equipped with a reflux condenser, suitable heating means and agitator is added-300 grams a diepoxy polyhydroxyl polyalkaryl polyether' known as Epon 828, 102 grams phenol, and 0.8 gram alpha methyl benzyldimethylamine and heated for four hours at 105 -115 C. .The reaction mass is cut back with 200 grams of methyl isobutyl ketone. Then, 15.3 parts of the above solution is mixed at room temperature with 11.6 parts of Mondur CB whose general formula has been discussed above (the isocyanate to hydroxyl ratio being 1.5 to 1). The material has a'pot life of about half an hour. The a liquid is applied to a cleaned steel surface by a brush, spray, or roller, and dries to a tack-free film in about an hour. The film has excellent impact resistance, ilexibility, and solvent resistance.

Example 11 Example 111 Using the apparatus of Example I, 176 grams of ortho cresol novolak epoxy, 93 grams phenol and 2% parts of alpha methyl benzyl dimethyl amine as a catalyst heated at 105-110 C. for one hour. The above reaction mass is cut back with 200 grams of methyl isobutyl ketone.

The above cut back reaction product is mixed at room temperature with 300 grams of Mondur CB whose general formula has been discussed above. The resultant him after curing has excellent chemical and solvent resistance. This film is much harder than the film of Example II. The foregoing has presented a novel composition usuable as'a paint or coating. This coating cures to form a film having excellent adhesive properties and is resistant to a wide range of solvents and chemical environments. The film has excellent resistance to passage of electricity where n is greater than 0.

2. The composition formed by mixing (a) an organic polyisocyanate having the general formula ILTCO l lOO with (b) a polyol having the general formula CH OH 6 with (2) a polyol having the general formula References Cited in the file of this patent UNITED STATES PATENTS OH 2,615,007 Greenlee Oct. 21, 1952 I 2,615,008 Greenlee Oct. 21, 1952 Q C I 5 2,788,335 Barthel Apr. 9, 1957 CH m 2,830,038 Pattison Apr. 8, 1958 2,833,740 Verbane May 6, 1958 2,959,571 Faeber Nov. 8, 1960 wherein a and b are substituent groups that do not contain carboxyl radicals, n has a value of at least 2, and m FOREIGN PATENTS m has a value of from 2 to the value of n. 522,895 Canada Mar. 20, 1956 

1. A POLYURETHANE COATING COMPRISING THE REACTION PRODUCT OF (A) AN ORGANIC POLYISOCYANATE 